Rotary screen for paper-making machines



Sept. 25 1923.

R. S. CLARKE ROTARY 503mm FOR PAPER MAKING MACHINES K Filed June 10 Patented Sept. 25, 1923.:

RALPH. S. CLARKE, OF WALPOLE, MASSACHUSETTS, "ASSIGNOB TO BIRD MACHINE COMPANY, A CORPORATION OF MASSACHUSETTS; a

ROTARY SCREEN FOR FAPER-MAKING MAGHINES.

' Application filed J'unelO, 1922. Serial No. 567.386.

To all whom it may concern:

Be it known that I, RALPH S. CLAnKm'a citizen of the United ,States, residing at Vv'alpole. in the county of Norfolk and State of Masachusetts, have invented certain new and useful Improvements in Botany Screens for Paper-Making Machines, of which the following is a specification.

This invention pertains to'rotary screens,

and relates more particularly to screens employed in the production of paper pulp. The structure is in a sense an improvement upon the screen such' as is shown in Letters Patent No.,1,210,996, issued to me under date of January 2nd, 1917, and to which reference is hadl Broadly stated the structure disclosed in the patent may be saidto comprise a rotatable screen surrounded by a vat or tank, and means whereb the tank or vat may be vibrated to pro uce a surge in the pulp mass in the vat and surrounding the screen,

thereby causing an inflow of the pulp through the screen mesh or openings.

The present invention has for its object the improvement of the screen structure, providing the same with means whereby the stock is agitated and at the same time prevented from traveling up and around with the screen rather than inwardly under the impulse action of the vibratory movement. In other words, the screen is provided with means such as a series of outwardly extending ribs or bafiles which in a sense produce a series of compartments which subdivide and confine the charge, preventing flow of the pulp along the screen surface and causing it, under the action of the vibration of the tank or vat, to move inwardly at more nearly right angle to the screen surface than would otherwise be the case.

In the drawing,

Fig. 1 is a transverse vertical section of the screen. the vat or tank and allied parts:

Fig. 2 is a perspective view of one end of the screen; and

Fig. 3 a similar view embodying a modification of the structure.

Referring to Figs. 1 and 2, 1 denotes the cylindrical shaped screen the cylindrical surface of which is perforate. One end is closed. by a head 2 while the other, 3. is open, as at 4. and is in direct communication with the usual discharge box or trough. Upon the exterior of the screen I provide a series of ribs 5, formed. as shown, of L-shaped" angle bars, the ribs being preferably equally spaced and radially arranged. A suitable means (not shown) may be employed to impart rotary. movement to the screen.

The scren,as in the patent before mentioned, is submerged, except. for its upper portion, in a vat or tank, denoted by 6, which is adapted to have a lateral vibratory motion imparted thereto at right angles to the axis of the screen. Such motion may be imparted through any suitable mechanism, thatiillustrated being the same as in the patent aforesaid, and comprising cradle like frames or castings 7 (only one being illustrated) supported at one side upon flexible members 8 and at itsopposite side by a link 9 pivotally sustained upon a column- 10'extending up from the base 11 of the machine. Frame 7 is provided with a downwardly extending arm 12 to whichis adjustably connected a pitman 13 adapted to be actuated through a cam 14.

The material to be screened is fed into the vat from supply troughs 15 and I6, and the 'coarse or rejected material passes out through a discharge opening 17. As will be seen upon reference to Fig. 1 the ribs 5 form in effect a series of pockets or compartments bounded by each pair of ribs. the

intermediate screen surface, and that portion of the vat wall which for the momenthappens to be opposite. By reason of this arrangement the pulp is prevented from traveling up or along the screen when it is thrown toward the exterior surface of the screen through the scillating movement of the vat; in other words. the charge with in the vat is in a sense subdivided and is arrested against upward flow and caused to move inwardly against the screen surface at more nearly right angles than does the charge where the ribs are not present. As a consequence, a greater output'is obtained and this without any measurable increase in power expenditure.

. In Fig. 3. the screen is similar to that shown in the-other: views except that the ribs 5 have secured to them rubber or other yielding strips 5 which admit of a closer fit between such strips and the tank or vat wall than can be had with the metal ribs alone. With this arrangement .the strips m ght contact. the vat wall when the vet is in one or the other of its extremes of movement; Without fear of damage to the parts. The strips will yield in case any hard or foreign substance should he caught between them and the wall of the vat.

With both forms the pulp is more th0roughly agitated than it is with the usual smooth exterior surface.

\Vhat is claimed ist- 1. In an apparatus ofthe character specified, the combination of a vat; means to vibrate the same; a screen mounted for rotation in the rat; and means interposed between the wall of the vat and the exterior surface of the screen for arresting flow of the pulp along the screen surface when the pulp is thrown inwardly toward the screen under vibratory movement of the rat.

2. ln'an apparatus of the character specified, the coniliiination of a vat; means to vibrate the same; a screen mounted for rotation in the rat; and means carried by theexterior of the screen to prevent flow of the pulp along the screen surface when. the pulp is thrown inwardly toward the screen under vibratory movement of the/vat.

3. In an apparatus'of the character specified, the combination of a vat; means to vibrate the same; a screen mounted for rotation in the vat; and a series of'radially disposed ribs extending along the exterior surface of the screen.

4. In an apparatus of the character specified. the combination of a vat; means to vibrate the same; a screen mounted for rotation in the vat; and a series of radially disposed ribs presenting flexible outer edges extending along the exterior surface of the screen.

In testimony whereof I have signed my name to this specification.

RALPH S. CLARKE. 

